Fall vegetable production is tricky because of staggered plantings, continued warm temperatures that encourage disease, hungry insects leaving harborage in summer weeds to attack young plants – not to mention rapidly changing weather conditions and winds that can blow in unwanted pests. The best defense is a good offense. Plan ahead to manage expected pest issues before they hurt crop establishment.
Whitefly Watch in Tomatoes
Don’t let previously light whitefly populations catch you off guard. Scout tomato transplants for silverleaf whitefly signs, especially around areas you weren’t able to totally clean up at the end of the season. Adult whiteflies are our main concern in the early season, since they can transmit pathogens. Later in the season, nymphs can cause problems by damaging leaves, causing irregular ripening and reducing interior fruit quality.
If you detect whitefly populations near treatment threshold, take action to limit feeding time and reduce the risk of transmission of diseases such as tomato yellow leaf curl virus. Controlling whitefly populations also promotes early crop vigor, which supports an abundant harvest.
We suggest choosing one of these programs for tomato insect control to promote fruit quality and uniformity:
- DuPont™ Verimark® insect control powered by Cyazypyr® in a tray drench or transplant water treatment (13.5 ounces per acre) improves crop establishment by reducing virus incidence when used as part of a virus management program. Use Verimark® along with a whitefly adulticide as needed and follow with a neonicotinoid 3 to 5 weeks later. To manage insect resistance when Verimark® is used at planting, do not use an IRAC group 28 insecticide for approximately 60 days after application.
- If additional treatments are needed to manage insect pests at the end of the season, use a foliar application of DuPont™ Coragen® insect control powered by Rynaxypyr® or DuPont™ Exirel® insect control powered by Cyazypyr®, following label directions.
- If you have no concerns about the performance you are getting with your current virus management program, you may want to stick with Coragen® for whitefly nymph suppression along with an effective adult whitefly control program. Start the season with your choice of neonicotinoid, followed by two applications of Coragen® 5 and 7 weeks later.
Don’t use more than one at-plant or two drip chemigation or soil injection applications of Verimark® per crop. Verimark®, Exirel® and Coragen® are Group 28 insecticides, so alternate with other modes of action to help manage and avoid resistance development.
Many diseases are spread by wind-driven rains that move pathogenic organisms from infected plant debris or soil to new plants. Bacterial speck and bacterial spot are two examples that can remain viable on plant debris for a year or more. Controlling the risk calls for field sanitation.
Other cultural practices that help reduce disease losses in tomatoes are listed in this set of friendly reminders from the University of Florida IFAS Extension:
- Use plastic mulch and staking to control fruit rots and reduce losses.
- Plant disease-free transplants or certified pathogen-free seed.
- Get rid of volunteer plants.
- Rotate crops.
- Increase soil pH.
- Set planting dates based on weather-related disease risk.
- Avoid extra thinning, pruning and other handling.
- Skip overhead irrigation.
- Eliminate weeds around fields in season and off-season.
Always read and follow all label directions and precautions for use. DuPont™ Coragen®, Exirel® and Verimark® are not available in all states. See your local DuPont sales representative or retailer for details on availability. Unless indicated, trademarks with ®, ™ or sm are trademarks of DuPont or affiliates. © 2016 DuPont.